Exploding hog barns beckon U researchers

A few years ago, hog farmers throughout the Midwest noticed foam building on top of their manure pits. Soon after, barns began exploding, killing thousands of hogs while farmers lost millions of dollars.

A team of University of Minnesota researchers is looking to find a fix for the foam that is plaguing hog farms.

The foam traps gases like methane and when a spark ignites it causes an explosion. About a half dozen barns in the Midwest have exploded since the foam was discovered in 2009.

In mid-September 2011, a barn in Iowa was added to the growing number of barns taken down by the foam. In the explosion, 1,500 pigs were lost, and one worker was injured.

Not only does the foam cause explosions but it also reduces manure storage volume and dirties the hogs.

The foam can reach heights of 4 feet. Farmers are encouraged to knock it down with water.

The researchers conduct their studies on commercial farms in Minnesota and surrounding states. Chuck Clanton, a bioproducts and biosystems engineering professor, said the team’s current approach is targeting how different microorganisms — primarily bacteria — developed in the manure pit. They think that a new set of species has formed in these pits in the last few years.

Larry Jacobson, another professor in the department, and his team haven’t found a solution for the foam but have discovered ways to curb its growth.

“We’re treating the symptoms but not getting to the cause,” he said.

The researchers still aren’t sure what causes the foam. But they have noticed a correlation between adding dried distillers grains in soluble — a product of the ethanol production process increasingly used in livestock diets — to the hogs’ diets and the foam, although that solution is too simplistic, Jacobson said.

“It’s very frustrating when you have two identical buildings sitting next to each other with same management, genetics, diets, etc. One foams, and the other does not,” Clanton said.

Pork production is an important source of income for Minnesota farmers and a billion-dollar industry in the state. According to data from the Minnesota Pork Board, the state’s pork farmers earned $2.1 billion in gross income from hog sales in 2010.

The state’s farmers have a lot at stake when this foam starts developing on their hog farms.

The average pig production building holds 2,000 or more pigs and costs about $600,000 to build. A heavier pig weighs about 250 pounds, and, within a few weeks of market, a barn filled with heavy pigs would be worth about $300,000. The cost of cleanup after an explosion combined with disposing of the dead hogs could easily cost a farmer up to $1 million, Jacobson said.

Not only will this research benefit the pork producers and their hogs but also the insurance companies of the facilities, Clanton said.

Funding for this research came from the Minnesota Agricultural Experiment Station, Rapid Agriculture Response Fund and the Minnesota Pork Producers Association.

The researchers will continue to search for a solution to the foam.

“So far, we are still working hard to understand the new phenomenon,” said assistant professor Bo Hu. “We’re trying to provide suggestions for farmers.”